Fish with cancer

Safia Danovi

Kat:: And now, moving from mice with teeth, we’re moving to fish with cancer. What’s this final story?

Dr. Danovi:: This is actually a really troubling story in that they found melanoma for the first time in a fish population. This is a wild fish population off the Australian coast out by the Great Barrier Reef and it’s worrying because it is a commercially important species of fish. This is the coral trout and it’s actually the first time that they found melanoma in fish. So it’s interesting and what’s particularly noteworthy, is that this part of the coast lies directly beneath the largest hole in the ozone layer.

Kat:: So they think that actually the loss of ozone is pretty much causing over-exposure by UV to these fish and it’s causing their cancers?

Dr. Danovi:: Yes, absolutely, I think they’ve ruled out sort of microbial pathogens and pollutions so at the moment, UV seems to be the most likely cause. I think they are going to have to prove that experimentally but they also did show that these melanomas that they found in these fish were quite similar to the melanomas found in humans. So, it wouldn’t be surprising if UV was the main cause.

Kat:: But how widespread is this? I mean melanoma in humans isn’t that common a cancer. What sort of numbers of fish were getting this disease?

Dr. Danovi:: So, they sampled just under 140 fish and they found around 15% of them had these melanoma lesions but of course, they suspect that the proportion of fish in the wild with melanoma is probably going to be much higher because, obviously, seriously ill fish are probably going to retreat and hide at the bottom of the ocean where they’re less likely to be caught and sampled, so we have no idea how widespread this problem is.

Kat:: So what do they plan to do next now that they’ve found this out?

Dr. Danovi:: I guess their next step would be first to look at the melanomas and characterise them and then of course, it begs the question: Are there any of the species of fish that are being plagued by this cancer type and that’s actually quite worrying.

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